Automobile-tire.



L. HOFMEISTER.'

AUTOMOBILE TIRE.

APPLICATloN FILED FEB. 9, 1918.

1,279,694. Pqtendsept. 24,1918.4

' sion.

EE0 HOFMEISTER, or MILWAUKEE, wIscoNsIixr.l

AUTOMOBILETIRE- Specicaton of Letters Patent. Patented Sept. 24, 1918.

` Application mea February 9, 191s. serial No. 2216,176. i

To all whom it may concern.'

Be it' known that I, LEO HoFMErsTER, a citizen' of tlie'United States, and resident of 'B'Iilwaultee in the Vcounty of I'Iilwaukee and State of 'isconsin, have invent-ed new and useful Improvements in Automobile-Ihres,

of which thefollowing is a description, refereiice being had to theaccompanying drawings, which are a part of this specification. The invention relates -to pneumatic Itires and has for its object to provide a puncture-v proof construction and one'in which the casing isi'elieved to a great` extent of ,side

strain.

The invent-ion is further designed to provide an automobile tire having an outer casing, an inner casing of limited expansibility, a layer or intermediate mass of yielding material, such as sponge rubber composition of some depth' interposed between said inner and outer casings, and `a pneumatic inner tube whichv when inflated holds the inner casing against the yielding material adja-` cent the tread portion of the outer casing and thereby holds said outer casing in ten- In the usual pneumatic tire construction the outer casing resists or limits the outward expansion of the inner tube. In the present invention the inner casing of limited expansibility limits the outward expansion of the inner tube and the outer casing is simply a tread member which will readily yield in all directions under strain in a manner similar to theouter casing of the usual pneumatic tire constructions.

The invent-ion further consists in the several features hereinafter set forth.

In the drawings:

Figurel is a side view of a portion of the tire embodying the invention, parts being broken away and' parts being shown in section;

Fig. 2 is a vertical sectional view of the tire;

Fig. 3 is a detail plan View of the inner casing, parts being removed;

Fig. is a detail sectional view ofthe in ner casing.

In general the tire consists of an out-er casing 5, an inner casing 6, an inner tube 7 within the casing 6, and an intermediate layer of sponge rubber or other yielding material 8 disposed between the outer casing 5 and inner casing 6.

The outer casing 5 may be of any desired construction `and ispreferably of the type readily removable from the rim, the drawings sliowing said casing provided with circumferential edges 9 which are hooked under or held by the curved flanges of the rim l0 so that when the. tire is inflated the outer casing will be firmly` in place upon the rim and on `deflation readily removed from said rim.. i r f.

The innercasing G is made up of fabric lport-ions and'rubber-ll vulcanized together to form al casing of limitedl expansibility, saidcasing being of less diameter than the outer casing soas to be.. disposed within it and be spaced from the tread portion of the outer casing and under normal conditions from the sides of said outer casing when inflated. This inner casing at' 1ts inner edges 12 has circumferentially extending wires 13 surrounded by rubber tube 14 embedded in said edges and layersl of friction cloth in itssides which friction cloth has no appreciable expansibvility transversely of thecasing and layers 16 of breaker cloth Cut on the bias, las shown in Fig. 3, to provide for limited Vexpansibility transversely of said casing, the cloth layers overlapping each other as shown in Fig. 4 and being impregnated with rubber and vulcanized in the usual manner to form a homogeneous structure.

IVith this construction of casing the inner" edges 12 are heldin place within the outer casing by the wires '13 and the layers 15 at the upper portion of said casing permit of limited expansibility.

Disposed within the inner casing .6 is the i usual inner tube 7, the edges 12 of said inner casing being spaced apart to permit ready insertion of said tube.

The intermediate layer of yielding material 8 is preferably a spongy rubber composition which is interposed between the fouter casing 5 and inner casing 6 to sub! stantially fill the space therebetween, the lower portion 17 of said composition being curved toconform to the curve of the casing 6 and there being normallyan air space 18 left between the inner land outer casings adjacent the rim 10 when the inner tube 7 is inflated. This material may be secured to the outer casing or be removable therefrom as desired. f

Vith this construction of tire when the inner tube 7 is inflated as shown in Fig. 2 it will lill the space' bounded bythe inner casing 6 and due to the non-expansibility of the sides of the inner casing and the limited eX- pansibility of the top portion of said casing, said tube will press upwardly against the spongy intermediate portion 8 which 1n turn will eXert pressure against the outer casing 5 to hold it in tension and thus keep it on the rim. In view of the spongy coniposition beneath the tread of the outer casing and the inner casing, it Will be Very diticult for any sharp element such as nails or tacks to pierce the inner tube 7. Also since the inner casing sustains the pressure of the inner tube and limits its expansibility the outer casing is relieved of side strains and thus side blow outs are prevented. Furthermore, the outer casing becomes simply a tread member the parts of which are in tension in the radial direction of the rim and the formation of the air space 18 bctween the inner and outer tires prevents puncture of the inner tube from the sides of the outer casing and also allows the inner casing to be compressed laterally under heavy pressures Without transmitting these pressures against the sides of 'the outer casing.

It will also be noted when the tire is in- ?lated and meets with an obstruction tending -to flatten the tread, that the outer casing will be tree to stretch laterally because of the local compressibility of the sponge rubber and under ordinary shocks the inner casing and tube will be little affected if at all because of the deadening or absorption of these shocks by the intermediate composition. I am aware that the details of construction herein shown and described are subject to some modication and change and I therefore desire it to be understood that such changes in construction as come within the scope of the appended claims I deem to be within the spirit of my invention.

What I claim as my invention is:

l. In a tire, the combination, with an outer casing, an inner easing disposed within the outer casing and spaced from the tread portion thereofl` said inner casing having inextensible inner peripheral edges, substantially inexpansible sides and a crown portion of limited expansibility, a pneumatic tube within said inner casing and exerting a pressure outwardly against the crown portion of the inner casing when expanded to hold the outer casing;` in tension, and a layer of yielding` material interposed between the tread portion of the outer casing and the crown portion of the inner casing.

2. In a tire, the combination of an outer casing, a separate inner casing of limited eX- pansibility and less tubular diameter than the outer casing to space said inner casing from the sides and tread portions of the outer casing, a layer of sponge composition interposed between said inner and outer casings but only partially lling the space therebetween to forni side air spaces when the tire is inflated, and a pneumatic inner tube within said inner casing.

3. In a tire, the combination of an outer casing, a separate inner casinghaving sides substantially inexpansible and a crown portion of limited expansibility transversely of said casing, a layer of yielding material ini terposed between said casings to space said inner casing from the tread portion of the outer casing and a pneumatic tube within said inner casing to hold said inner casing under pressure and thereby hold the outer casing 1n tension and relieve said outer casing of side strain from the expansion of said inner tube.

In testimony whereof, I affix my signature.

LEO HOFMEISTER. 

